Process of treating bituminous sand-rock.



rock was hardened TED SATES PATENT oFFIcE.

,PROCESS OF TREATING BITUMINOUS SAND-ROCK.

No Drawing.

To all whom it may concern:

Be it known that I, HENRY F. WILLIAMS, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented new and useful Improvements in Proce ses of Treating Bituminous Sand- Rock, of which the following is a specification.

My present invention relates to a process of treating bituminous sand rock to form paving material or the like.

In my U. Letters Patent No. 770,137,

dated September 13, 190 c,Idisclosedaprocess of treating bituminous sand rock which consisted in softening said rock and then mixing with it lime-sludge produced in the manufacture of beet-sugar, whereby the said and toughened. This treatment adapted the bituminous sand rock for paving, roofing and other purposes. I have discovered a method of treating said bituminous sand rock to form the above products, whereby its use is greatly extended, and said products are greatly cheapened. A difiiculty experienced in practicing the process described in said patent Was found to be that, after digging the material from the earth and placing it in cars, wagons, or ships for transportation to the place where it is to be used, said material would be found, on arrival at its point of destination, to have conglomerated or cohered into a single mass. Consequently, practically the same amount of work which had been expended in originally digging out the rock would have to be done all over again in extracting it from the ship or car, and, at an even greater: expense on account of the cost of demurrage. Consequently the use of this process was limited to localities and conditions where this extra expense could be avoided, and in the great majority of cases the extra cost thus entailed was either alto-- gether prohibitive or greatly reduced the profit which should have been derived from the process.

In my improved process, the sand rock when it is first removed from the earth is in pieces of all sizes but in this condition has very little adhesive property, and therefore is easily reduced to pieces of the size of gravel. In this condition, it is now coated with lime-sludge, that is, with the same material with which it is afterward compounded. This coating is preferably effected by throwing the material into an agitator con- Speciflcation of Letters Patent. Application filed August 4, 1910. Serial No. 575.394.

Patented Feb. 7, 1911.

taining said lime-sludge, in which being agitated it takes up a sutlicient. coating of said lime-sludge to prevent the pieces adhering to one another. In this condition it is placed in the cars or vessels for transportation and arrives at its point of destination in the same condition, conglomeration of the pieces having been prevented by the lime-sludge coating. A coating of other material than lime-sludge could be used toprevent this con glomeration, although less effective in pro ducing final results, on

affinity between the carbonic acid in the limesludge and the hydro-carbon in the bituminous sand roek, so that when limesludge is used the result is a great increase in cohesion and hardness. These pieces so coated can now be taken to the street which is to be paved, and there laid down in a layer of suitable thickness, raked smooth. and tamped down by suitable tamping means, and finally rolled with the heated roller.

By the above operations the coating of lime sludge will become incorporated in the bituminous sand rock, causing the same to become tough and hard. and the upper surface especially, which is thus rolled and heated, becomes homogeneous in character. It will be observed, however, that in the above process the pieces of sand roe; are heated very slightly, if at all, and herein is the distinctive feature of the present invention.

In my former process. and in all prior processes, so far as I am aware in which bituminous rock is used for paving purposes and the like, a considerable amount of heat has been applied to the rock. It has heretofore been thought necessary to melt the bitumen to cause the pieces to adhere together, and even to add water thereto to soften it, all of which is just the opposite of What should be don I find that any heat more than that which will expel the moisture contained in the rock is injurious, and in this respect my invention is an improvement upon prior processes. In my process I apply no more heat than is necessary to dr the rock.

When the sand rock is in pieces of the size of gravel, the moisture contained therein is very easily expelled, the heat of the tools by which it is handled being sufficient for this purpose. I may, instead of directly tamping the pieces of rock down in the place Where the paving is to be laid, ap-

account of the strong the hydro-carbon .porize the moisture contained in the rock.

ply heat thereto in a suitable agitator, but I take care that the degreeof heatthus ap plied is no more than is necessary to va- If the heat temperature, of the bitumen are unimpaired, whereas, it the heat be raised to a greater temperature, then the bitumen loses to a reater or less extent its adhesiveness, probalily because of the carbcnization which then takes place of )resent in the rock. ,By my process this car onization is avoided.

A-fair imitation of bituminous sand rock itself can be produced by combining clean dry sand with asphaltic oils in sand rock, and this product will absorb a like amount of lime-sludge under like conditions of heat and mechanical manipulation. I therefore regard it as within the scope of my iIlY8I1-. tion to treat in the manner above described such a 'roduct of clean dry sand and heavy asphaltic oils, and I desire the term bi tuminous sand rock in the claims to be understood as a generic term including the artificial product above referred to.

I claim:-- v v 1. The method of treating bituminous sand rock which-consists in mixinq' it with lime-sludge and Sub ecting it to a eat only suficientto dry it without volatilizing any of. the hydrocarbon constituents thereof, and then ressing it into the desired form, substantia ly as described.

2. The rocess of treating bituminous be thus kept below the above the natural adhesive properties small pieces, coating said pieces with lime-sludge to an extent to prevent the adhesion of the pieces, subjecting said pieces 10 a low heat and pressing the pieces, so heated, to the required form, substantially as described.-

comp'arati el sand rock which consists in coating pieces thereof with lime-sludge to an extent to prevent the adhesion of the pieces, subjectthe pieces so heated to the required form, substantially as described.

4. The process of treating. the bituminous sand rock which consists in reducing it to comparatively small pieces, coating said pieces with pulverulent material and mixing themwith lime-sludge, subjecting said mixture to a low heat and pressing the stantially as described.

.5. The process of treating bituminous sand rock which consists in reducing it to comparatively pieces with lime-sludge to an extent to prevent the adhesion of the pieces, arranging said pieces in the desired form, 'andthen subjecting the pieces to considerable pressure, substantially as described. 7

In testimony whereof I have hereunto set 1 my hand in the presence of two subscribing witnesses. v

. HENRY F. WILLIAMS. Witnesses:

FRANCIS M. lVnion'r,

sand rock which consists in reducing it to D. B. RICHARDS.

3; The process of treating bituminouspieces so heated to the required form, sub-' small pieces, coating said ing' said pieces to a low heat, and. pressing 

